The invention relates to a terminal for mobile communication, for example a so-called handset or cordless telephone. In such apparatus various energy-saving modes are activated by evaluation of operating states, which energy-saving modes prolong the so-called life of the apparatus which usually utilize a rechargeable power supply source. Therefore, such apparatus are usually equipped with a liquid crystal display having a very low power consumption.
It is an object of the invention to reduce the power consumption in an apparatus of the kind set forth.
This object is achieved by a control device arranged to disconnect, partially or completely, a display device from a mobile communication terminal in dependence on one or more operating states.
Surprisingly it has been found that disconnection of a part of the display device also yields a reduction of the power consumption in liquid crystal displays. Until now such disconnection was considered to be superfluous, because the power consumption of the other parts of a terminal imposes far higher power requirements also in the standby mode. As steps for reducing the power requirements in the standby mode become more and more effective, however, such a power-saving step also has noticeable effects on the standby time.
Complete disconnection of the display device involves the risk that the user is given the wrong impression that the power supply source in the terminal apparatus is fully exhausted. In a special embodiment, therefore, all parts of the display device are deactivated except for the part showing the name and/or the logo of the mobile radio operator at which the terminal is checked in at the time.
The decision as to when the terminal apparatus should enter the operating state in which it partly or completely deactivates the display device can in principle be taken in a time-dependent manner, for example by measurement of the time elapsed since the last actuation of a key. Additional sensors, such as a light-sensitive sensor or a motion-sensitive sensor, for example, can switch off the display device completely, for example when the terminal apparatus is present in the dark. In this case a display is fully useless, since a user cannot make out anything without additional backlighting which, as is generally known from the state of the art, can be activated only by actuation of an arbitrary key. A motion-dependent sensor can switch the display device, for example from partial display to full display again. This makes sense, for example, when a terminal rests in an immobile state, for example on a table. Full display is then activated again by touching the terminal.